1. Field of the Invention
This invention relates to earthmoving apparatus and in particular to heavy-duty rippers for installation on earthmoving apparatus.
2. Description of the Prior Art
To loosen earth for facilitated handling by bulldozers, scrapers and the like, the surface of the earth may be first treated by pulling a ripper therethrough. The ripper comprises a plurality of teeth, or ripper tips, which extend downwardly into the earth and rip furrows in the earth as the ripper is pulled along the surface.
Such ripping action requires a high tractive force. To provide such force, it has been conventional to use a pair of tractors. One such dual tractor arrangement is shown in U.S. Pat. No. 2,998,965 of Donald J. Larson, owned by the assignee hereof, wherein a push block on the draft assembly of a ripper is provided for receiving the thrust of a pushing tractor in addition to the dragging force applied through a shank-supporting pin on a pulling tractor.
In U.S. Pat. No. 3,266,816 of Robert A. Peterson et al, owned by the assignee hereof, a draft assembly is provided for use with tandem coupled tractors for distributing the stresses from a pulled ripper to the bodies of both tractors.
In Owen D. Evans' U.S. Pat. No. 3,496,844, a pair of traction units carries an intermediate digging, mixing, and earth moistening unit having harrow elements depending from a beam structure thereof. Means are provided for lowering and raising the harrow elements.
The Robert N. Stedman U.S. Pat. No. 3,552,497, owned by the assignee hereof, shows the use of a pair of tractors in side-by-side tandem relationship with a rear cross brace structure having a ripper tooth mounting member thereon.
In U.S. Pat. No. 3,245,488 of Robert A. Peterson, owned by the assignee hereof, and No. 3,324,963 of Donald H. Stroot et al, owned by the assignee hereof, steering controls for steering tractors in series tandem relationship are disclosed.